Scottish police officers are to "withdraw goodwill" at 5pm today in a pay dispute.
The Scottish Police Federation (SPF) is to begin its "most overt" action in a century.
Scottish officers are protesting about a "derisory" £565 pay rise offer.
The BBC says that, by law, officers cannot take industrial action, but will now charge for all overtime and refuse to begin shifts early.
Police Scotland said it was committed to seeking a pay settlement through the Police Negotiating Board.
The £565 pay offer made to officers was rejected by the governing body of the SPF, representing rank-and-file officers, last week.
In a letter to members on Thursday, SPF general secretary Calum Steele said he had received communication from the official side of the negotiations - which includes the Scottish Police Authority, Police Scotland and the Scottish Government.
Discussions to resume
He added that it would enable discussions on the pay claim to resume, but later clarified on Twitter that the withdrawal of goodwill would go ahead as planned today.
Mr Steele previously told members the action was not taken to "frustrate any investigation, or further aggravate any victim's experience".
"It is simply to demonstrate to our employers just how much discretionary effort, and free policing hours, they ordinarily take for granted," he added.
He said the action was necessary to persuade their employers to "return to the negotiating table with a fair pay offer".
The leader of the Scottish Conservatives, Douglas Ross, raised the issue at First Minister's Questions on Thursday.
Nicola Sturgeon claimed that police officers were suffering from a cost-of-living crisis "exacerbated by the Tory government".
BT workers vote to go on strike
Meanwhile, thousands of BT workers have voted to go on strike in a dispute over pay.
Some 30,000 Openreach engineers and 9,000 BT call-centre workers were balloted and overwhelmingly backed industrial action, the Communication Workers Union (CWU) said.
General secretary Dave Ward told the BBC that BT now faced its first national strike since it was privatised in the 1980s.
BT said it was disappointed and would "work to keep our customers and the country connected" if staff walked out.
Mr Ward said he expected BT to offer a "significantly-improved" pay rise by next week or strike dates will be set.
CWU said the potential strike action would have a serious effect on the roll-out of broadband and could cause big problems for those working from home.
This year BT gave staff a £1,500 per year pay rise, but CWU said that with price rises at record highs "this is a dramatic real-terms pay cut".
A BT spokesperson said the company had awarded its highest pay rise for frontline colleagues in more than 20 years - an average 5% increase and up to 8% for those on the lowest salaries.